Hello,
I have a project which needs 'some power' when AC power shuts down, to e.g. do some processing and send information via SIM7600.
I use normally an AC Power adapter 230Vac/9Vdc to power an UNO. But some testing learns that when AC power fails, the UNO almost instantaneously shuts down. By adding a capacitor as kind of backup power, I hope to solve my problem. A few seconds of extra power autonomy would already be great.
best regards,
Geert
Sounds like a great idea but that will take a lot of capacitor depending whet else is connected to the Arduino. I would suggest using a USP if you need lines support or a battery backup system for the Arduino. Here is the formula you need: capacitance in Farads F = Current I x time t / voltage dV
I would suggest it is not as simple as just adding a capacitor. First in needs to be a very big capacitor but most important of all there must be some way of detecting that the mains input has failed.
I used to design circuits like this when I worked in the set top box industry and they are not as simple as just adding a capacitor.
Consider how your capacitor will be charged. It will be a SHORT circuit for several seconds while it is charged. Can you afford that to happen with your design?
1 Like
Yeah... you can save a variable to two to flash but for what you want to do, you'll probably need a battery. Sometimes super capacitors are used to keep RAM memory powered but they are not usually used to power a microprocessor.
Capacitors make terrible batteries because of their discharge curve is the opposite of what you want in a battery. You want a battery that holds most of its voltage as it discharges. Capacitor voltage drops drastically as soon as you start drawing current and then it levels-off after it's near zero and mostly discharged.
1 Like
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.